June 6, 2011

New research finds that gestational diabetes, or pregnancy-related diabetes, may not raise the risk of heart disease independent of other cardiovascular risk factors except in certain high-risk populations, such as Hispanics. The results will be presented Monday at The Endocrine Society's 93rd Annual Meeting in Boston.

"The prevalence of gestational diabetes is increasing, and its impact for the mother can extend well beyond pregnancy by raising her risk of developing type 2 diabetes and heart disease," said study co-author Rhonda Bentley-Lewis, MD, of Massachusetts General Hospital in Boston, where the study was performed

"However, we found that gestational diabetes does not confer the same cardiovascular risk to every woman," she said.

Bentley-Lewis called this large population study the first to examine the racial impact on the risk of heart disease after gestational diabetes. She and her colleagues studied more than 800 women who delivered infants and had a diagnosis of gestational diabetes between 1998 and 2007. The researchers compared these participants with a control group of more than 3,200 women who had no history of diabetes during pregnancy. They matched cases and controls by their total number of pregnancies.

After delivery, women were followed for a median of 11.9 years for the development of cardiovascular disease, specifically heart attack, stroke and high blood pressure, as indicated by medical records. Women who developed Type 2 diabetes during that time were excluded from further analysis.

The investigators found that gestational diabetes alone did not predict which women would get heart disease apart from other risk factors, such as older age and high blood pressure. However, when they analyzed the study participants by racial-ethnic group, black race and Hispanic ethnicity predicted heart disease even after adjusting for other risk factors. In particular, Hispanic women with past gestational diabetes were 70 percent more likely to develop heart disease than their Hispanic counterparts without pregnancy-related diabetes.

"Hispanic women with gestational diabetes developed heart disease to a greater degree than would be predicted," Bentley-Lewis said, adding that more research is needed to learn why.

"Physicians should closely monitor women with a history of gestational diabetes, to control their heart disease risk factors," she said. "Their risk for cardiovascular outcomes might differ by race or by factors that we didn't evaluate."